from django.contrib.auth import get_user_model
from django.db import models
from django_extensions.db.models import TitleDescriptionModel

from book.models import Module


class ObjectiveGroup(models.Model):
    class Meta:
        verbose_name = 'Lernziel Gruppe'
        verbose_name_plural = 'Lernziel Gruppen'

    title = models.CharField('title', blank=True, null=False, max_length=255)

    module = models.ForeignKey(Module, blank=False, null=False, on_delete=models.CASCADE)
    # a user can define her own objectives, hence this optional param
    user = models.ForeignKey(get_user_model(), blank=True, null=True, on_delete=models.CASCADE)

    def __str__(self):
        return 'ObjectiveGroup {}-{}-{}'.format(self.id, self.module, self.title)


class Objective(models.Model):
    class Meta:
        verbose_name = 'Lernziel'
        verbose_name_plural = 'Lernziele'

    text = models.CharField('text', blank=True, null=False, max_length=255)

    group = models.ForeignKey(ObjectiveGroup, blank=False, null=False, on_delete=models.CASCADE)

    def __str__(self):
        return 'Objective {}-{}'.format(self.id, self.text)


class ObjectiveProgressStatus(models.Model):
    class Meta:
        verbose_name = 'Lernzielstatus'
        verbose_name_plural = 'Lernzielstatus'

    done = models.BooleanField('Lernziel erledigt?', default=False)

    objective = models.ForeignKey(Objective, blank=False, null=False, on_delete=models.CASCADE)
    user = models.ForeignKey(get_user_model(), blank=True, null=True, on_delete=models.CASCADE)

    def __str__(self):
        return 'Lernzielstatus {}-{}'.format(self.objective, self.done)